Effects Of Night Warming On Growth And Reproductive Trait Of Vicia Sativa

Under the background of global warming,the temperature change shows obvious asymmetry.For example,the increase of temperature at night is greater than that during the day.The research on how night warming affects the yield and quality of forage seeds will help us to specifically predict the effect of climate change on the production of forage seed,and to provide theoretical basis for grass seed industry to actively respond to climate change.Therefore,in the present study,the effects of night warming on the growth characteristics,seed yield and quality of Vicia sativa were determined.The main results are as follows:(1)When the daily average temperature is same,compared with symmetrical warming,asymmetric warming had no significant effect on seed germination percentage of Vicia sativa,but significantly increased seed germination rate.(2)Compared with control group(CK),night warming at vegetative growth phase(VW),reproductive growth phase(RW)and whole growth phase(VRW)led to an average advance of 1-6 days in each phenological period of Vicia sativa,and,especially,the effect of VRW treatment was the most obvious.VRW treatment made the Vicia sativa phenophase 2-6 days earlier than CK.The growth period of CK,VW,RW,and VRW treatments was 98,95,94,and 92 days,respectively.(3)The growth indexes of Vicia sativa were significantly enhanced by night warming,especially VRW treatment.The plant height,total biomass,aboveground biomass,underground biomass,specific leaf area and SPAD value under the VRW treatment were increased by 33.0%,79.8%,80.4%,16.6%,14.6% and 47.8%,respectively,compared with CK.(4)Night warming significantly affected the seed yield of Vicia sativa.Compared with CK,the pod biomass,seed yield and harvest index of Vicia sativa were significantly enhanced with VW,RW,and VRW treatments.The seed yield with CK,VW,RW and VRW treatments were 10.3,18.6,16.2 and 21.1 g,respectively.Theseed yield of VRW was enhanced by 105.8%,which was the highest among these three treatments.(5)Among the seed yield components,VW,RW and VRW significantly enhanced the number of reproductive branches per plant,pods per reproductive branche,seeds per pod and 1000-seed weight.Correlation analysis and path analysis showed that the number of reproductive branches per plant was the most important factor affecting seed yield.(6)Night warming significantly affected the seed quality of Vicia sativa.Compared with CK,VW,RW and VRW enhanced the seed size and seed longevity of Vicia sativa,and reduced the seed vigor,indicating that night warming improved the seed quality to a certain extent.(7)The response of seed germination of Vicia sativa to temperature and water potential varied with the warming period.At 25? and 10/20?,the germination percentage of Vicia sativa seeds was significantly enhanced by three night warming treatments,but only VRW significantly increased the seed germination percentage at15/25?.Under the condition of water stress,there was no significant difference or significantly increase in germination percentage between CK and night warming treatment.